RE: [AMRadio] RE: GB> Update On Supply for PP 304TLs: W9TB Homebrew Pics
Well, it could be done. and I have thought about it. But one step at a time. I have so many projects that making this one bigger right now just doesn't fit the time available. Thanks. 73, Don Merz, N3RHT -Original Message- From: Donald Chester [mailto:[EMAIL PROTECTED] Sent: Friday, November 15, 2002 4:31 PM To: amradio@mailman.qth.net Subject: RE: [AMRadio] RE: GB> Update On Supply for PP 304TLs: W9TB Homebrew Pics >From: "Merz Donald S" <[EMAIL PROTECTED]> >It is amazing, I think. The ham I bought it from was going to part it out! >I said no way--this is worth saving. It is CW only but I am also going to >try using it for RTTY. >73, Don Merz, N3RHT > With the spacing on the PA tuning cap I bet you could plate modulate it at a full kilowatt and nothing would arc over. Why not use it for AM, with a suitable modulator? Don K4KYV _ MSN 8 with e-mail virus protection service: 2 months FREE* http://join.msn.com/?page=features/virus ___ AMRadio mailing list AMRadio@mailman.qth.net http://mailman.qth.net/mailman/listinfo/amradio
RE: [AMRadio] RE: GB> Update On Supply for PP 304TLs: W9TB Homebrew Pics
From: "Merz Donald S" <[EMAIL PROTECTED]> It is amazing, I think. The ham I bought it from was going to part it out! I said no way--this is worth saving. It is CW only but I am also going to try using it for RTTY. 73, Don Merz, N3RHT With the spacing on the PA tuning cap I bet you could plate modulate it at a full kilowatt and nothing would arc over. Why not use it for AM, with a suitable modulator? Don K4KYV _ MSN 8 with e-mail virus protection service: 2 months FREE* http://join.msn.com/?page=features/virus
RE: [AMRadio] RE: GB> Update On Supply for PP 304TLs: W9TB Homebrew Pics
It is amazing, I think. The ham I bought it from was going to part it out! I said no way--this is worth saving. It is CW only but I am also going to try using it for RTTY. 73, Don Merz, N3RHT -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Sent: Wednesday, November 13, 2002 10:48 AM To: amradio@mailman.qth.net Subject: Re: [AMRadio] RE: GB> Update On Supply for PP 304TLs: W9TB Homebrew Pics Truely incredible, Don! All I could do at first was to marvel at the craftmanship. I kept shaking my head is disbelief. I still am. I can not get over all those vent holes he put in the sheet metal! One thing that struck me amoung all that fine craftsmanship is the final tuning cap. this gentleman truely knew how much voltage that cap must withstand. he didn't fudge. enjoy that station. 73 Mike WA5CMI > Thanks to the generous hospitality of Bill Coleman, N2BC (a callsign that > deserves a set of chimes!), a pretty good set of photos of the incredible > W9TB > homebrew station is posted on > > http://home.stny.rr.com/n2bc > > Tell me what you think. > 73, Don Merz, N3RHT > > > -Original Message- > From: Merz Donald S [mailto:[EMAIL PROTECTED] > Sent: Thursday, November 07, 2002 1:00 PM > To: amradio@mailman.qth.net; [EMAIL PROTECTED] > Subject: RE: GB> Update On Supply for PP 304TLs > > > Well, I have discovered the errors of my own making here. Your comments > helped > me realize where I had gone astray. > > First, let me say a few words in my own defense. Most homebrew rigs that are > passed along come with no documentation. A few come with some documentation. > And > one in a hundred comes with good documentation. This "W9TB Desk Kilowatt" is > in > that middle group. In this case, the partial builder's notes that I have were > ambiguous and I mis-interpreted them. The power supply notes that I have are > for > the 4E27-based exciter--not for the 304TL's final amp. I have almost no > information on the final amp supply that W9TB used. But I screwed up and > thought > his cryptic notes were for the final amp. > > Sooo...I only discovered my mistake when your comments started me thinking > about > the use of the word "screen". Finally it dawned on me that the notes I was > looking at were for the exciter. Screen actually meant screen, not grid. Now > it > all makes sense. But it means that I am worse off than I thought for > information > on his original 304TL supply design--there is basically none. > > At the risk of boring you, let me back off here and describe this rig so you > have a complete picture. In a word--incredible. Imagine the finest mechanical > and electrical engineering skills pumped into a late-40's homebrew CW > kilowatt. > It's a complete station with receiver, frequency meter, monitor receiver, > exciter, and final. It has provision for antenna rotor control on the front > > panel. And it has provision for a remote control console attachment. Based on > the notes, the rig was built in 1948-49, updated frequently over the years > and > used on the air until about 1985. I will take some pictures and pass them > along. > > The control console, receiver and exciter are built on top of a removable > desktop. Each has its own compartment that it fits into. The desktop itself > appears to be commercial. But everything else is built from scratch--sheet > aluminum with aluminum bracing. The receiver has been extensively > solid-stated. > I have not even opened it up yet. But I believe it is 100% solid state. I > have > opened up the band switching exciter and it is awesome. The construction > quality > is nothing short of intimidating. It uses a 4E27 final and a National MB-150 > tank circuit. It is otherwise partly solid-stated. The transmitter and > receiver > both use National PW dials for tuning. > > The two pedestals that hold up the desk are packed with gear. The left hand > > pedestal holds the final amp--push-pull 304TLs with the biggest plug-in coils > that B&W ever made and a variable center link operated by a turns-counter > lever > on the front panel. One side of the pedestal is a safety-interlocked door > that > opens to provide easy access to the final. The other pedestal has a Meissner > HF > receiver built into the top section, followed by a home-made heterodyne > frequency meter and a drawer for holding the final coils. I have not looked > at > the Meissner receiver and freq meter at all. > > The power supply for this rig was built into a closet in W9TB's house. The > parts > of the power supply that I have are whatever was salvaged from that cl
Re: [AMRadio] RE: GB> Update On Supply for PP 304TLs: W9TB Homebrew Pics
Truely incredible, Don! All I could do at first was to marvel at the craftmanship. I kept shaking my head is disbelief. I still am. I can not get over all those vent holes he put in the sheet metal! One thing that struck me amoung all that fine craftsmanship is the final tuning cap. this gentleman truely knew how much voltage that cap must withstand. he didn't fudge. enjoy that station. 73 Mike WA5CMI > Thanks to the generous hospitality of Bill Coleman, N2BC (a callsign that > deserves a set of chimes!), a pretty good set of photos of the incredible > W9TB > homebrew station is posted on > > http://home.stny.rr.com/n2bc > > Tell me what you think. > 73, Don Merz, N3RHT > > > -Original Message- > From: Merz Donald S [mailto:[EMAIL PROTECTED] > Sent: Thursday, November 07, 2002 1:00 PM > To: amradio@mailman.qth.net; [EMAIL PROTECTED] > Subject: RE: GB> Update On Supply for PP 304TLs > > > Well, I have discovered the errors of my own making here. Your comments > helped > me realize where I had gone astray. > > First, let me say a few words in my own defense. Most homebrew rigs that are > passed along come with no documentation. A few come with some documentation. > And > one in a hundred comes with good documentation. This "W9TB Desk Kilowatt" is > in > that middle group. In this case, the partial builder's notes that I have were > ambiguous and I mis-interpreted them. The power supply notes that I have are > for > the 4E27-based exciter--not for the 304TL's final amp. I have almost no > information on the final amp supply that W9TB used. But I screwed up and > thought > his cryptic notes were for the final amp. > > Sooo...I only discovered my mistake when your comments started me thinking > about > the use of the word "screen". Finally it dawned on me that the notes I was > looking at were for the exciter. Screen actually meant screen, not grid. Now > it > all makes sense. But it means that I am worse off than I thought for > information > on his original 304TL supply design--there is basically none. > > At the risk of boring you, let me back off here and describe this rig so you > have a complete picture. In a word--incredible. Imagine the finest mechanical > and electrical engineering skills pumped into a late-40's homebrew CW > kilowatt. > It's a complete station with receiver, frequency meter, monitor receiver, > exciter, and final. It has provision for antenna rotor control on the front > > panel. And it has provision for a remote control console attachment. Based on > the notes, the rig was built in 1948-49, updated frequently over the years > and > used on the air until about 1985. I will take some pictures and pass them > along. > > The control console, receiver and exciter are built on top of a removable > desktop. Each has its own compartment that it fits into. The desktop itself > appears to be commercial. But everything else is built from scratch--sheet > aluminum with aluminum bracing. The receiver has been extensively > solid-stated. > I have not even opened it up yet. But I believe it is 100% solid state. I > have > opened up the band switching exciter and it is awesome. The construction > quality > is nothing short of intimidating. It uses a 4E27 final and a National MB-150 > tank circuit. It is otherwise partly solid-stated. The transmitter and > receiver > both use National PW dials for tuning. > > The two pedestals that hold up the desk are packed with gear. The left hand > > pedestal holds the final amp--push-pull 304TLs with the biggest plug-in coils > that B&W ever made and a variable center link operated by a turns-counter > lever > on the front panel. One side of the pedestal is a safety-interlocked door > that > opens to provide easy access to the final. The other pedestal has a Meissner > HF > receiver built into the top section, followed by a home-made heterodyne > frequency meter and a drawer for holding the final coils. I have not looked > at > the Meissner receiver and freq meter at all. > > The power supply for this rig was built into a closet in W9TB's house. The > parts > of the power supply that I have are whatever was salvaged from that closet > including the pole pig. It's hard to make sense out of what is here. > > I think I have HV, screen and filament covered for the exciter from my > extensive > "junk-box" power supply collection. But the junk box let me down on the final > supply. I have no transformer capable of replacing the pole pig. It looks > like > w9TB was running the HV for both the exciter and the final from the > pole pig. > But there are no chokes in the "closet parts" that I received with the rig. > And > some hefty chokes will be needed. So I am only going to run the final from > the > pole pig and use the junk box supply as-is--unchanged (a lucky break) for the > exciter. > > So that's where this stands. I have no web site. But if someone has somep
RE: [AMRadio] RE: GB> Update On Supply for PP 304TLs
BTW here is a link to a PDF file on the 304TL http://www.aiko.com/roscoe/304tl.pdf
RE: [AMRadio] RE: GB> Update On Supply for PP 304TLs
Hi Donald: I used to run a pair of 304TLs Push Pull on 75 meters. It was a real brute of a rig and really had lots of head room for modulation. As I recall for Class C Plate Modulated you will need about -500 volts of bias at about 150 ma of grid current (75 ma / tube). I used a combination of fixed and grid leak to get the -500 volts. I think it was about -100 from a shunt regulated bias supply and the rest was from a grid leak resistor. The exciter was a Push Pull pair of 812s. I ran about 1600 volts at around 600ma on the 304s. The thing would put a solid 800 watts into a dummy load (read with many different meters). I wanted to run the lower voltage of 1600 Volts because I didn't want any arc over on the plate tank capacitor. It was a split stator from a BC610. The spacing on it didn't look like it would handle a lot of voltage and modulation too. I used shunt coupling to the output tank with a couple of 500pf large ceramic capacitors and a special hand wound center tapped RF choke. I used another Christmas tree style choke from the center of the home brewed choke to the HV supply point. This kept the HV off the tank capacitor and the coil at the same time. I recall I had trouble getting the thing to load to enough current at first so I took some turns off of each end of the B&W plug in tank coil until it took almost all of the capacitance of the split stator to resonate it on 3850 MHz (it would not go to the CW end of the band). I then parallel tuned the link with a .001 ceramic (a large one). Now I could get some current to flow when I pushed in the link. The 1600 Volts / 700 ma also made a nice match for the modulator which was 4 - 813s AB2 (2750 Volts on the plates) conventional Push Pull Parallel circuitry. That modulator would easily take the plate of the 304s from their static 1600 volts to 4200 volts on a positive peak. And the 304s head room would follow the modulation right on up to the peak at 7200 Watts PEP output. But alas, I moved and just didn't have the room for a driver that was as big a Globe King 500 plus a 6 ft rack of power supplies and final. So I switched to a pair of 250ths. Not quite as high on the plate efficiency but a lot easier to drive. Good luck on yours. I hope you have as much fun as did. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Merz Donald S Sent: Thursday, November 07, 2002 12:00 PM To: amradio@mailman.qth.net; [EMAIL PROTECTED] Subject: [AMRadio] RE: GB> Update On Supply for PP 304TLs Well, I have discovered the errors of my own making here. Your comments helped me realize where I had gone astray. First, let me say a few words in my own defense. Most homebrew rigs that are passed along come with no documentation. A few come with some documentation. And one in a hundred comes with good documentation. This "W9TB Desk Kilowatt" is in that middle group. In this case, the partial builder's notes that I have were ambiguous and I mis-interpreted them. The power supply notes that I have are for the 4E27-based exciter--not for the 304TL's final amp. I have almost no information on the final amp supply that W9TB used. But I screwed up and thought his cryptic notes were for the final amp. Sooo...I only discovered my mistake when your comments started me thinking about the use of the word "screen". Finally it dawned on me that the notes I was looking at were for the exciter. Screen actually meant screen, not grid. Now it all makes sense. But it means that I am worse off than I thought for information on his original 304TL supply design--there is basically none. At the risk of boring you, let me back off here and describe this rig so you have a complete picture. In a word--incredible. Imagine the finest mechanical and electrical engineering skills pumped into a late-40's homebrew CW kilowatt. It's a complete station with receiver, frequency meter, monitor receiver, exciter, and final. It has provision for antenna rotor control on the front panel. And it has provision for a remote control console attachment. Based on the notes, the rig was built in 1948-49, updated frequently over the years and used on the air until about 1985. I will take some pictures and pass them along. The control console, receiver and exciter are built on top of a removable desktop. Each has its own compartment that it fits into. The desktop itself appears to be commercial. But everything else is built from scratch--sheet aluminum with aluminum bracing. The receiver has been extensively solid-stated. I have not even opened it up yet. But I believe it is 100% solid state. I have opened up the band switching exciter and it is awesome. The construction quality is nothing short of intimidating. It uses a 4E27 final and a National MB-150 tank circuit. It is otherwise partly solid-stated. The transmitter and receiver both use National PW dials for tuning. The two pedestals that hold up the desk are packed wi
Re: [AMRadio] RE: GB> Update On Supply for PP 304TLs
Don, it sounds nifty! I have plenty of room on my homepage (storage space for pix, etc). I'd be glad to whoop together some pages for you. If you want, send over the pix & some words to go with each & I'll build a page or 3 or 6. 73, Bill Bill ColemanN2BC http://home.stny.rr.com/n2bc - Original Message - From: "Merz Donald S" <[EMAIL PROTECTED]> To: ; <[EMAIL PROTECTED]> Sent: Thursday, November 07, 2002 12:59 PM Subject: [AMRadio] RE: GB> Update On Supply for PP 304TLs Well, I have discovered the errors of my own making here. Your comments helped me realize where I had gone astray. First, let me say a few words in my own defense. Most homebrew rigs that are passed along come with no documentation. A few come with some documentation. And one in a hundred comes with good documentation. This "W9TB Desk Kilowatt" is in that middle group. In this case, the partial builder's notes that I have were ambiguous and I mis-interpreted them. The power supply notes that I have are for the 4E27-based exciter--not for the 304TL's final amp. I have almost no information on the final amp supply that W9TB used. But I screwed up and thought his cryptic notes were for the final amp. Sooo...I only discovered my mistake when your comments started me thinking about the use of the word "screen". Finally it dawned on me that the notes I was looking at were for the exciter. Screen actually meant screen, not grid. Now it all makes sense. But it means that I am worse off than I thought for information on his original 304TL supply design--there is basically none. At the risk of boring you, let me back off here and describe this rig so you have a complete picture. In a word--incredible. Imagine the finest mechanical and electrical engineering skills pumped into a late-40's homebrew CW kilowatt. It's a complete station with receiver, frequency meter, monitor receiver, exciter, and final. It has provision for antenna rotor control on the front panel. And it has provision for a remote control console attachment. Based on the notes, the rig was built in 1948-49, updated frequently over the years and used on the air until about 1985. I will take some pictures and pass them along. The control console, receiver and exciter are built on top of a removable desktop. Each has its own compartment that it fits into. The desktop itself appears to be commercial. But everything else is built from scratch--sheet aluminum with aluminum bracing. The receiver has been extensively solid-stated. I have not even opened it up yet. But I believe it is 100% solid state. I have opened up the band switching exciter and it is awesome. The construction quality is nothing short of intimidating. It uses a 4E27 final and a National MB-150 tank circuit. It is otherwise partly solid-stated. The transmitter and receiver both use National PW dials for tuning. The two pedestals that hold up the desk are packed with gear. The left hand pedestal holds the final amp--push-pull 304TLs with the biggest plug-in coils that B&W ever made and a variable center link operated by a turns-counter lever on the front panel. One side of the pedestal is a safety-interlocked door that opens to provide easy access to the final. The other pedestal has a Meissner HF receiver built into the top section, followed by a home-made heterodyne frequency meter and a drawer for holding the final coils. I have not looked at the Meissner receiver and freq meter at all. The power supply for this rig was built into a closet in W9TB's house. The parts of the power supply that I have are whatever was salvaged from that closet including the pole pig. It's hard to make sense out of what is here. I think I have HV, screen and filament covered for the exciter from my extensive "junk-box" power supply collection. But the junk box let me down on the final supply. I have no transformer capable of replacing the pole pig. It looks like w9TB was running the HV for both the exciter and the final from the pole pig. But there are no chokes in the "closet parts" that I received with the rig. And some hefty chokes will be needed. So I am only going to run the final from the pole pig and use the junk box supply as-is--unchanged (a lucky break) for the exciter. So that's where this stands. I have no web site. But if someone has someplace I can post some pictures, I would like to hear from you. Thanks. 73, Don Merz, N3RHT -Original Message- From: Merz Donald S [mailto:[EMAIL PROTECTED] Sent: Friday, November 01, 2002 3:28 PM To: amradio@mailman.qth.net; [EMAIL PROTECTED] Subject: GB> More On Supply for PP 304TLs "Screen" is what the original builder's notes show instead of "grid" or "bias". So I was propagating the mis-wording when I used "screen." The 304TL is of course a triode. Otherwise the audiophools could not love it. It looks like he was running the grid bias at about 80 volts. He had the primary of the HV transformer connected to a motorized variac that slowly
